Method of making fastening means



March 14, 1939. G, A. TINNERMAN METHOD OF MAKING FASTENING MEANS Filed Oct. 4, 1937 2 Sheets-Sheet 2 i j/ I j?" g55 s 30 I @50H55 A. FNA/ ENNA /v Patented Mar.v 14, 1939 PATENT OFFICE ,2,150,852 ME'rnon or MAKING FASTENING MEANS George A. Tlnnerman, Rocky River, Ohio, assignor to Albert H. flinnerman, Cleveland, Ohio Application October 4., 1937, Serial No. 167,310

14 Claims.

This invention relates to an improved method for working sheet metal parts such as panels, plates and various forms of connecting devices to adapt the same for receiving a threaded fastening member. An example of such a method for providing fastening means is disclosed in a copending application, Serial Number 133,202, led March 26, 1937, of which the present application is a continuation in part, and which has since issued as Patent No. 2,096,387, October 19, 1937. l

More particularly, this invention contemplates a method for providing a sheet metal part with integral fastening means into which an ordinary bolt or screw fastening may be threaded and advanced to final applied position to be automatically held in locked fastening engagement against unscrewing, displacement or otherwise working loose incident to jarring, vibration and strain set up in the members secured.

The fabrication of sheet metal structures comprising parts secured bybolt or screw fastenings threaded in such parts has heretofore been found generally inefiicient and unsatisfactory in that the sheet metal parts, being relatively thin, are of insuiiicient thickness to provide openings having walls of suitable area with which threads of a bolt or screw fastening may coengage to be retained eiiectively in applied position. In such sheet metal installations it is wellknown to be impracticable to tighten a threaded member in an opening thus provided, since the threads thereof are easily stripped by the axial drawing action incident to tightening, thereby causing the opening to become enlarged to the extent that the threaded member is loose in final applied position, subject to displacement and unscrewing, and otherwise results in a faulty, loose installation which is practically useless.

In certain methods, such as, for example, that disclosed in the copending application above referred to, fastening means may be provided in sheet metal structures by deforming elements out of the plane of the sheet to engage the threads of a threaded member at a point removed from the surrounding area to prevent the fastening elements from being pulled therethrough when the threaded member is drawn up. In the aforesaid mentioned application, the method disclosed embodies, generally speaking, a number of steps by which the fastening means are provided by drawing and stretching an area of the sheet to provide a substantial wall of greater area than the space from which it is drawn, the enlarged wall thus obtained being provided with a suitable opening to receive a threaded member thereby presenting cooperating fastening elements which cannot pull through onto the reverse side of the sheet when a threaded member applied thereto is advanced to tightened, 5 locked, fastening position.

The instant-invention marks an improvement over this method in that the elements of the fastening means provided are suitably worked or deformed, simultaneously with a novel punching 10 operation, to have a specific configuration providing a strengthened cross-section intermediate their lengths and with the bolt engaging extremities thereof so disposed as to adapt the same for uniform threaded engagement throughout with the threads of a threaded member applied thereto. Thus, due to their strengthened crosssection, the elements of the fastening means so provided, are capable of withstanding extraordinary strain and pressure in the application of the threaded member thereto, while the speciiic disposition of the bolt engagingiextremities ensures that the same have uniform threaded engagement throughout with the threads of the threaded member in tensioned, locked engagment therewith in final applied fastening position.' I

The foregoing advantages of the fastening means provided by the method of the instant invention may be best appreciated -When it is considered that in certain installations in which an unhardened sheet metal part such as a panel Ais secured, it is often necessaryA or desirable to employ a hardened screw-threaded member capable of cutting its own threads in a. cooperat- 35 ing sheet metal part. Heretofore, it has been found that the use of hardened screws in such installations is both inefilcient and impractical in that the metal of the sheet, being relatively soft and malleable, the areas immediately surrounding the opening receiving the screw give way easily when the inherently harder screw is drawn up tov the extent that the elements comprising the screw thread engaging areas of .the adjacent walls are lmutilated and easily pull -through onto thereverse side of the sheet thereby resulting in a loose, faulty fastenlngengagement.

In other installations it is often necessary to securey a member to a sheet metal part made ofv spring metal. In such constructions the spring metal material is harder than that of the screws in which instance the fastening means provided therein tend to cut away and strip the threads of the threaded member when advanced to applied fastening position. Inasmuch as fastening l. 5g

elements provided in spring metal by the method of the instant invention are so formed at their extremities as-to engage the threads of a bolt .uniformly throughout, there is little tendency for the threads of the threaded member to become mutilated, cut away or stripped as it is tightened. to locked engagement with the fastening ele-- ments. l

It is therefore a primary object of the present invention to provide a method of preparingk unhardened sheet metal with a form of fastening the fastening means.

Another primary object contemplates a method for providing in hardened sheet metal such as spring steel, a fastening means comprising elements adapted to engage the threads of a threaded member'uniformly throughout thereby minimizing stripping or mutilating of the threads thereof on beingapplied to tightened, fastening engagement.

Another object of the instant invention contemplates the provision ina sheet metal part, of fastening means comprising cooperating independently movable elements having wall areas of such cross-section as to provide for increased strength and rigidity throughout their lengths to withstand the axial drawing action of a threaded member applied thereto.

A` further object of the invention comprehends a method by which fastening means are provided in sheet metal, in which the fastening elements thereof, at their extremities, correspond substantially to the cross-section of the threaded member and are suitably shaped to lie on a helix corresponding to the pitch of the threads of the threaded member for uniform threaded engagement therewith throughout.

A still further object is for an improved method of working sheetmetal for receiving a threaded member comprising the provision of cooperating, independentlymovable elements of suitable design adapted for locking fastening engagement with a threaded member in applied fastening position without distorting or mutilating the fastening elements or the threads of the threaded member such that they may be disassociated and again employed in the same or a similar installation.

Further objects and advantages of the invenn tion will be apparent to those skilled in the art as a description thereof proceeds with reference to the accompanying drawings in which like reference characters designate like parts throughout the same, and in which:

Fig. 1 is a top plan view of a sheet metal panel or like'member having fastening means provided therein by the improved method of the instant invention and comprising cooperating fastening elements receiving threaded members in uniform threaded engagement therewith;

Fig. 2 is a section along line 2-2 of Fig. 1, looking in the direction of .the arrows, showing in detail the fastening elements, provided'by the improved method, in uniform threaded` engagement with a threaded member throughout in applied fastening position;

Figs- 3, 4, and illustrate in plan the improved method of providing fastening means as embodied in a series of steps, Fig. 3 showing the ini- ILIIKLBISBv tial step of slitting and punching an opening of specific configuration in the sheet metal part to define the fastening elements;

Fig. 4 shows the step in the method by which the fastening elements so defined, are worked longitudinally as to have a cross-section providing increased strength therein and with the extrem-y ities thereof so disposed as to present an opening corresponding substantially to the cross-section of the threaded member;

Fig. l5 illustrates the final step in the me/thod by which the extremities of the fastening elements are suitably shaped and trued to lie on a helix corresponding to the threads of the threaded member for uniform threaded engagement therewith throughout;

Figs. 6, 7, and 8 are various views of the step in the method represented in Fig. 4, Fig. 6 being anedge elevation, Fig. 7 being a section taken on line 1-1, and Fig. 8 being a section taken along line 8 8, respectively, looking in the direction of the arrows;

Figs. 9, 10, and l1 are various views of the step illustrated in Fig. 5, Fig. 9 being an edge elevation, Fig. 10 being a section on line lll- IIL and Fig. 11 being a section on line II-il respectively, looking in the direction of the arrows; Y

Fig. 12 shows in edge elevation the elements of a completed fastening means with a threaded member about to be applied thereto vin an installation;

Fig. 13 shows `a threaded member as appliedl to locked fastening lengagement in an installation comprising fastening elements provided by the method of the instant invention; and,

Fig. 14 is a top plan view' of an installation such as represented in Fig. 13 showing the elements of the fastening means provided by the improved method as disposed inv uniform threaded engagement throughout with the threads of a bolt applied to locked fastening position.

Figs. 15 to 23 inclusive show a further embodiment of the improved method for providing a modined form of fastening means, Fig. 15 representing in plan the initial step of slitting and punching an opening of specific configuration in the sheet metal part thereby defining the fastening elements to be formed therefrom; *j

Fig. 16 shows in plan the step in the method by which the fastening elements so designed are worked longitudinally to have a cross-section providing increased strength therein and with the extremities thereof so disposed as to present an opening corresponding substantially to the crosssection of the threaded member to be applied thereto;`

Fig. 17 illustrates 1n plan the anal step of this embodiment by which the extremities of the fas- -tening elements are suitably shaped and trued to lie on a helix corresponding to the threads of the threaded member to have uniform threaded engagement therewith throughout:

Figs. 18 and 19are various views of the step represented in Fig. 16 of this embodiment of the method, Fig. 18 being a section on line IB-IB, and Fig. 19 being a section on line |9-i9 respectively, looking in the direction of the arrows;

Figs. v20, 21 and 22 are various views of the step of the method illustrated in Fig. 17, Fig. 20 being a section on line 2li- 20 thereof, Fig. 21 being s, section n line 2 I-Zi, and Fig. 22 being a section on linen-22 respectively, looking in the direction of the arrows; and, i Fig, 23 shows in edge'elevation, the elements f ment of the improved method in which the fastening means comprises an additional fastening element making for greater strength in an installation, Fig. 24 ,representing in plan the initialv step of slitting and punching an area of a sheet metal part to define therespective fastening elements;

Fig. 25 illustrates in plan the completedfastenin g means as provided in this embodiment of the improved method;

Figs. 26 and 27 are various views of the completed fastening means illustrated in Fig.25, Fig. 26 being a section taken along line 2li-26, and Fig. 27 being a section taken on line 21-2'l, respectively, looking in the direction of the arrows;

Fig. 28 shows a. threaded member as applied lto locked fastening engagement in an installation comprising fastening elements providedA in this embodiment of the improved method, the fastening elements being so designed as to engage two distinct threads of the threaded member; and,

Figa 29 shows a threaded member as applied to locked fastening engagement in an installation comprisingnfastening elements provided by this embodiment of the improved method, the -fastening elements being so designed as to engage three binding action becomes most pronouncedand positive when the threaded memberv is driven home to tightened fastening position to the extent that the fastening elements snugly engage the thread vthroughout .and dig into and become embedded in the lroot of the threaded member thereby providing a .locked fastening engagement from which the threaded member cannot work loose under extraordinary conditions of wear, vibration and strain and over long periods of use. n

It has been found in the art ofsecuring sheet metal parts by bolts and screws, the mere provi sion of an opening in a sheet metal part to receive a threaded member is noteffective to provide a fastening means in which a threaded member may bel applied and drawn up as necessary to provide a tight, rigid installation. However, as by the method of this invention, if such an opening is provided `in conjunction with distinct elements which are struck and vformed to project materially out of the plane of the sheet, such projecting elements serve 'to bolster the thread engaging extremities thereof and thus prevent the same from being pulled through'onto the reverse side of the metal sheet when a threaded securing member is applied thereto and drawn taut.

In several prior patents applicant has disclosed various methods and. arrangements for obtaining such fastening means, butin each instance it is to be noted that the elements comprising the fastening' meansl are substantially fiatl or'arched intermediate their lengths, and, at their extremities present a'substantially dia'- mond shaped opening. Thus, the extremities of the fastening elements in presenting a substantial diamond opening, do not engage the thread of a threaded member throughout but` only at spaced points; this arrangement together with the fact that the fastening elements intermediatetheir lengths are fiat or arched and thereby readily yieldable, makes for a fastening means to which a threaded member may be quickly applied to home position in a direct axial thrust or substantial rachet-like action and then rotated a quarter turn or more to tighten and lock in such home position. Such fastening means for quickly assembling and securing sheet metal parts are highly advantageous for speed andeconomy in present day mass production and accordingly have been readily accepted 'by the trade and now have a wide range of use. However, it has been found that in working in relatively thick sheet metal parts, for example, such forms of fastening means are'not capable of the added strength required and accordingly it has been found necessary to sacrifice some of V the' aforesaid speed possible in assembling operations, vbut compensate therefor by providing fastening elements which are not as yieldable but which are-.inherently stronger and capable of withstanding any ordinary reasonable requirement which heretofore has necessitatedthe use of individual nuts, .bolts and lock washers and the tedious, time consuming operations necessary inthe application thereof in an installation., Generally speaking, the added strength obtained in fastening elements provided in sheet metal by the instant method is the result of several entirely new teachings; thus, the fastening elements are each formed with a sub- Stantial corrugation throughout their lengths providing increased strength therein; the extremities of the fastening elements present an opening complementary to the cross-section of the threaded member for substantial line contact with the root diameter thereof at points substantially at right angles to its longitudinal axis; and the trued disposition of the extremities of the' fastening elements to lie on a.helix corresponding to that of the threads of the threaded member provide for'uniform threaded engagement therewith throughout. Accordingly', by the method of the present invention integral fastening means may be effectivelyv provided in relatively heavy sheet metal parts of any size in an installation such as represented in Figs. 1 and `2 in which, for example, a panel member A provided with a series of bolt receiving means each comprising cooperating fastening elements Il, l2, may be secured as by bolts IIJ passing through apertures in a supporting member B. Y

Referring more particularly to Figs. 3 to 11 inclusive ofthe drawings, S'designates a sheet metal part which maybe a fragment lof any sheet metal structure in which it is desired to provide fastening means to secure such part by means of a threaded member such as a common screw, bolt, sheet metal screw or hardened tapping screw. In the instant method for providing fastening means in the sheet metal part, a suit.- able area of the sheet S, Fig. 3, is worked as by punching an irregular, substantially egg-shaped opening |15 together, with suitable slits I3, I4, thereby defining distinct, independent elements Il, I2; thus the extremities of the fastening e1ements or thewalls of the opening thus provided are initially, substantially elliptical in form and the opening itselfis of a size substantially smaller than the minimum cross-sectional are'a of the u threaded member to be applied thereto. The punched and slit area thus provided defining the fastening elements is then subjected to aforming operation by a suitable forming die acting more particularly upon the independent fastening elements throughout their lengths to press the same out of the plane of the sheet metal part into substantial elongated corrugations I'I, I8, Figs. 4 and 6 to 8 inclusive. This forming operation disposes the fastening elements I I, I2 in substantially oppositely disposed relation projecting out of the plane of the sheet with each of said elements having a cross-section substantially in the form of a corrugation as shown at Il, Fig. 8. At the same time, by virtue of this corrugating operation of the fastening elements I I, I2, the extremities thereof are distorted from their substantially elliptical, egg-shaped configuration Il, Fig. 3, into a circular opening I6 in plan, Fig. 4, corresponding in size substantially to the area of the threaded member at its root diameter. It will vtherefore be understood that by this forming operation, the opening is not only enlarged to correspondto the minimum cross-sectional area of the threaded member to be applied thereto, but also provides corrugations extending substantially throughout the lengths of the fastening elements and disposes the same in materially projecting relation above the plane of the surrounding area of sheet metal from which they have been deformed. Thus the fastening elements by reason of the corrugations provided therein, are made inherently stronger and by reason of their projecting relation above the plane of the sheet are so disposed at their extremities as to engage a threaded member applied thereto on lines substantially asat right angles to the longitudinal axis thereof such that in the operation of tightening the threaded member, the extremities of the fastening elements will more naturally tend to dig into the grooves-intermediate the threads and root diameter thereof at a point removed from the plane of the sheet, thereby minimizing and practically defeating any possibility of the same pulling through onto the reverse side of the sheet.

The final step in the method is disclosed in Flgs.'5 to 11 inclusive; and this step may involve a separate operation or be.. incorporated in the step described with reference to Figs. 4 and 6 to 8 inclusive. In this step, the oppositely disposed elements II, I2 now corrugated'as at II, Il, Figs. 6 to 8 inclusive, are subjected to a suitable operation by which the extremities of said elements are moved from their substantially oppositely disposed relation, Fig. 6, and shaped and trued to lie`on a helix corresponding to that of the thread- A ed member to be applied thereto substantially as shown in Figs. .,9 and 12. In this operation the configuration oflthe `truly circular opening II, shown in plan in Fig. 51s not disturbed but rather,

only theextremities of the fastening elements f are shaped to lie atdefinite points projecting out of the plane of the sheet S; thus the wall portion or extremity 20 of fastening element I2'lies on a` helix but even at its lowest point .isfdenitely above the plane of the sheet and in such relation as to readily receive the'leading thread of the threadedmember introduced thereto and thereafter coact with the opposed element II, the extremity is 6: which comprises the highest points ofthe helix. Since said extremities Il, 2l of the fastening elements II, I2 as stated. present a substantiallytruly circular opening I6, and are also dlsposedgona helix corresponding to thethrest of the threaded member, they naturally are adapted to engage the bolt throughout and in uniform threaded engagement with any thread thereof at all points. Thus the maximum binding action of the extremities of the fastening elements with the ad of the bolt is ensured thereby providing in this respect, unsual holding ability and strength in the fastening means. Upon continued rotation of a threaded member, this uniform threaded engagementof the extremities of the fastening elements with the threads thereof becomes pronounced and positive in a tightened installation to the extent that the extremities tend to dig into the grooves intermediae adjacent threads and become embedded in the root diameter of the threaded member in locked fastening engagement therewith.

'Ihe unusual strength and-holding ability of fastening means provided insheet metal by the instant method may be better understood from a consideration of Figs. 12 to 14 inclusive showing a sheet metal part A provided with fastening means II, I2 and which is to be secured to a supporting part B by a threaded member I0 shown about to be applied thereto. Inasmuch as the lowest point of that portion of the helix dened by the extremity 2l is directly in line withthe leading thread of the threaded member, the bolt may be quickly applied thereto and readily advanced axially by the usual turning action. As

the leadingthread oi' the bolt III is rotated the same contacts the remaining portion of the helix defined by the extremity I9, such that in any position the said extremities I9,'20 are' in uniform threaded engagement throughout withthe thread of the bolt substantially as shown in Figs. 13 and 14. Further rotation. of the bolt causes the fastening elements II, I2 to become tensioned and of course have a tendency to move toward the plane of the sheet, but due to the corrugated cross-section thereof, the fastening elements are possessed of unusual inherent strength and thus tend more eii'ectively to move toward each other and dig into the groove intermediate the adjacent threads and also embed into the root diameter of the threaded member in locked frictional, fastening engagement therewith. Thus such further rotation ofthe screw may be said to cause a tensioning action and progressively increasing frictional engagement between the extremities of the fastening elements and the root diameter of the bolt until the engagement thereof is such that the sheet metal element is rigidly secured and any vibration, jarring,.or strain in the structure cannot cause displacement, reverse rotation or tend toward unscrewing of the bolt from applied position.

It will therefore be seen that in the instant method the fastening means provided require no special treatment other than forming and shaping. The elements may be provided in unhard- ,ened relatively thick sheet metal parts such as panels and thelike, individually or in mutiple, to afford a most eillcient securing arrangement making for extreme economy in the fabrication thereof, especially in mass production. The fastening means as provided by the method of the instant invention may be just as well prepared for even greater holding ability in tempered or other specially treated metal such as spring steel.` In any arrangement, it will be understood that incorporated in any sheet metal structure and enables the attachment of parts to said structurebymeansofthreadedmemberswhichsreu Still further rigidity and locking action in anA installation may be obtained by the use of a threaded member such asa sheet metal screw having a deep thread and a pitch greater than the thickness of the fastening elements'. And, if desired, the sheet metalpart in which the fastening means are provided may be in the form of a disc or plate usable in the manner -of a nut and in this respect the plate would have a function analogous to that of a self-locking nut. Also in any arrangement, due to the fact that the specific fastening means provided comprise distinct independentlyv movable members, each fastening element is capable of automatically setting in locked fastening engagement with the cooperating portion of the thread of the threaded member without becoming mutilated orj permanently distorted to the extent that it may not again be effectively employed. Thus, the fastening elements provided as by the instant method are advantageous over any heretofore known form of similar fastening means in that' they son 5 er'most portion of the helix being directly in the plane of the sheet, the leading. thread of the threaded member is most easily engaged there-I with in a rapid, quick turning movement thereby providing for greater speed in assembling operations. However, more important is the fact that the element I2, comprising the lowermost point of the helix 20, that is, that portion of the lower fastening element which would be the irst to tend to pull through the sheet on drawin g up of the bolt, cannot possibly give way since it is integral with the sheet as at 30 and thereby provided with the maximum strength possible at its most vulnerable point.

Figs. .24-28 inclusive show the method of the instant invention as developed in a further embodiment in which still greater strength may be obtained in the fastening means provided. The

`)method as followed in this embodiment incormay be applied in an installation and, if desired,

readily disassociated from the cooperating m'eans of either of said embodiments may be inthreaded member and again employed in-,the

same or similar installation.

Figs. 15-23 inclusive show the method of the present invention as developed in another embodiment by which further added strength may be obtained in the fastening means provided. The method as followed with respect to this embodiment is substantially identical to that disclosed with reference` to Figs. 1-14 inclusive except in the ment of the method shown in Figs. -15 to 23 inclusive for basic elements II, I2, is included, an additional fastening element 40, is provided from the plane of the sheetS", as by a-slitting and l punching operation along lines 4I with the exinv this embodiment substantially as described above with reference to Figs. 1-14 inclusive making due provision, of course, in the design of the forming die for the area 30 in which the element I2 is integral. Thus, in the next succeeding step illustrated in Fig. 16', the element II, I2 are corrugated throughout their lengths as at I8, Fig. 19 providing increased strength therein and at the same time causing the opening I5. Fig. 15, presentedby the extremities I9, 20, of the fastening elements to be enlarged to a truly circular configuration as at I6, Fig. 16, the element I2 however, remaining integral in the plane of the sheet S', as shown at 30, Fig. 18. 1n the final step in which the extremities I9, 20, of the elements II, I2 are shaped and trued to Alie on a helix corresponding to that 'of the threads of the threaded member substantially as illustrated tremity 42. of such element being defined by a perforation 43. This auxiliary fastening element, thus provided, is bent by a suitable forming operation out of the plane of the vsheet in a Areturn bend 44 substantially as indicated by dotted lines, Fig. 24 with the extremity 42 thereof so disposed as to lie in registration with the extremity of fastening elementf'l! substantially as illustrated. in Figs. 25 and 26. As shown in Fig. 27, the said `fastening element 40 may be corrugated throughout its length for increased strength with the extremity 42 thereof suitably shaped to lie on a helix corresponding to that ofthe threads of the threaded member.v Thus, as shown in Fig. 28, the basic fastening elements II, I2 are provided to operatein the usual manner as described above, engaging one thread of the threaded member` I0 throughout, and the. element 40 acts in in Fig. 1'7, the truing of the element I2 neces-- sarily begins at the plane of the sheet since this element is integral therewith at such point. This may be seen in Figs. 20 and 21 wherein element extremity of the cooperating fastening element.

I I, Fig. 22. Accordingly, the completed fastening means presented in this embodiment -of the method of the invention appears substantially as conjunction therewith engagingthe next. adjacent thread thereby providing greater strength inthe fastening means not only from the standpoint that more than one thread of the threaded member is effectively engaged, but also, by reason of the fact that the basic fastening elements II, I2 are relieved of a proportionate degree of strain 'when the threaded member is drawn up to tightened, locked fastening engagement.

Fig'. 29 shows an alternate construction of this embodiment of the invention wherein each of the fastening elements IIa, I2a, and 40a engage disvtinct threads 'of the threaded member thereby providing for even greater strength and locking l place at spaced points throughout the length of aktion. Thus the lowermost thread Ila, preferably integral in the plane of the sheet B'f as illustrated in the embodiment of Fig. 23, engages the lowermost effective thread of the bolt, the oppositely disposed cooperating element Ha engages the next adjacent thread, and the auxiliary element 40a engages the next or third thread such that the strain set up in the fastening elements as the bolt is drawn up is evenly distributed and the binding action ofthe extremities thereof takes the threaded member.

While the method of this invention hasbeen described in detail with specific examples, such examples are illustrative only, since it will be apparent to those skilled in the art that other embodiments within the spirit and scope of the invention may be practiced without departing from the teachings or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come Vwithin the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

l. The inethod of working sheetI metal to provide fastening means adapted to receive a threaded fastening, which comprises, slitting and punching an area of the sheet to define an elementfor threadedly engaging said threaded fastening, and forming said element ofthe fastening means into a substantial longitudinal corrugation extending substantially throughout the width thereof thereby providing for increased strength therein.

2. The method of working sheet metal for providing means adapted to receive a threaded -mem- Aber, which comprises, slitting and punching an area of th'e sheet to define an element having an irregular shaped extremity, and deforming said element longitudinally into a substantial corrugation extending substantially its full width thereby providing. for increased strength therein A and shaping the extremity thereof to correspond substantially to the cross-section of the threaded member.

3. 'I'he method of working sheet metal for providing -means adapted to receive a threaded member, which comprises, slitting and punching an area of the sheet to define an element having an irregular shaped extremity, and deforming said element longitudinally into a substantial corrugation extending substantially its full width thereby providing for increased strength therein and shaping the extremity thereof to correspond substantially to the cross-section of the threaded member, and truin'g said extremity to lie on a helix corresponding to that of the threads of the threaded member for uniform threaded engagement therewith throughout.

4. The method of working sheet metal for providing means adapted to receive athreaded member, which comprises, slitting and punching an area of the sheet to define distinct, independently movable elements adapted to coact inengaging a threaded member applied thereto, and forming at least one ofsaid elements into a substantial longitudinalcorrugation extending substantially throughout the width thereof thereby providing for increased strength therein.

5. mmm ofwomngsneetmem improvidingmeansadaptedtoreeeiveathreadedmember, which comprises, slitting and punching an area of the sheet to define distinct, independently movable elements adapted to coact in engaging a threaded member appliedthereto, and forming at least one of said elements into asubstantial ionvfor increased strength therein and shaping the extremity thereof to correspond substantially to the cross-section of the threaded member, and

truing said extremity to lie on a helix corresponding to that of the threads of the threaded member for uniform, threaded engagement therewith throughout.

'1. The method of working sheet metal for providing means adapted to receive a threaded member, which comprises, slitting an area of the sheet to denne distinct independently movable elements, punching the elements so defined to provide at least one with an irregular shaped extremity, forming said element longitudinally into a. substantial corrugation extending substantially throughout the width thereof thereby providing for increased strength therein and shaping the extremityvthereof to correspond substantially to the cross-section of the threaded member.

" 8. The method of working sheet metal for providing means adapted to receive a threaded member, which comprises, slitting an area of the sheet to define distinct independently movable elements, punching the elements so definedto provide at least one with an irregular shaped extremity, forming said element longitudinally into a substantial corrugation extending substantially throughout the width thereof thereby providing y for increased strength therein and shaping the extremity thereof-to correspond substantially to the cross-section of the threaded member, and truing said extremity to lie on a helix corresponding to that of the threads of the threaded mem-- ber for threaded engagement therewith throughout.

9. The method of working sheet metal for providing means adapted to receive a threaded member, which comprises, slitting and punching an area of the sheet to define ajplurality of disthict, independently movable elements having irregular shaped extremities, deforming the elements so defined intov corrugations extending substantially the full. width thereof to provide increased strength therein and an opening therebetween corresponding' substantially to the4 cross-sectional area of thethreaded member. A

1Q. The method of working sheet metal for providing means adapted to receive a threaded member, which comprises, slitting and punching an'area of the sheet to define a plurality of distinct, independently movable elements having irregular shaped extremities,l d` ei'orming the elev ments so deilnedlinto corrugaiicms extending substnntntuy the m11 width therf to provide for increased strength therein and an opening thereu annessa. l l

member which comprises. slitthig an area of the between corresponding substantially to the crosssectionalareaofthethreadedmemher,andshap ing the extremities thereof for uniform threaded ent with the threads of the threaded g member throughout.

11. The method of working sheet metal for providing means adapted to receive a threaded member, which comprises, slitting and plmching an area oi' the sheet to define a plurality of distinct,

1. independently movable elements havingirregular shaped extremities, deforming the elements so defined into corrugations extending substantially the full width thereof to provide for increased strength therein and an opening therebetween 1; corresponding substantially to the cross-sectional area of the threaded member, and truing said extremities to lie on a helix corresponding to that of the threads of the threaded member for uniform threaded engagement therewith throughout. A12. The method of working sheet metal for providing means adapted to receive a threaded member which comprises, slittingan area of the sheet to deiine distinct, independently movable elements, punching the elements to provide the ing the elements into'corrugations extendingl substantially the full width thereot to provide for increased strength therein and .to project materially out of the plane of the sheet and to shape said irregular shaped extremities -to correspond substantially to the cross-sectional area of' the threadedl member.

13. The method of working sheet metal for providing means adapted to receive a threaded same with irregular shaped extremities, deformsheet to denne distinct, independently movable elements, punching the elements to provide the same with irregular-shaped extremities, deforming the elements longitudinally into substantial corrugations extending` substantially throughout the width thereof and projecting materially out ofthe plane oi?l the sheet thereby providing for increased strength therein and shaping said irregular-shaped extremities'to present an opening therebetween corresponding substantially to the cross-sectional area of the threaded member, and'truing said extremities to lie on a helix corresponding to that of the threads of the t 1readed member for uniform threaded engagemen therewith throughout.

14. The method of working sheet metal for providing means adapted to receive a threaded member which comprises, slitting an area of the sheet to define distinct, independently movable elements, punching the elements to provide the extremities thereof with a substantial oval- 'shaped opening therebetween, deforming the eleing materially out of the plane of the sheet thereby providing for increased strength therein and shaping said oval-shaped opening to substantially truly circular to correspond to the cross-sectional area of thel threaded member. and truing said extremities to lie on a helix corresponding to the threads of the threaded member for uniform threaded engagement therewiththroughout.

y GEORGE A. TINNERMAN. 

